RU2524108C2 - Device for making of articles from composite by transfer forming - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to production of composite parts by transfer forming. Device for making the part from composite by resin injection comprises the die to accommodate the article billet that can be impregnated with resin. Note here that is composed of female die and one or several movable structural components to be arranged on said female die. Note here that after assembly made unit forms the cavity with profile corresponding to that of the article.

EFFECT: perfected readjustable and replaceable tooling.

11 cl, 3 dwg

Description

The invention relates to a device for manufacturing products from a composite material by transfer molding, as well as to a method of using this device.

It is known from the prior art that it is possible to form articles of composite material by impregnating the fibers with resin and, in particular, in closed form.

First of all, as an example of molding methods, one can cite the transfer molding method, for which the term RTM method is used in the literature (from the English Resin Transfer Molding).

According to this method, a group of reinforcing fibers is placed in a special way around the support, and then this group is placed inside a closed form, the profile of which essentially corresponds to the profile of the manufactured product.

In the case of the traditional RTM method, this form consists of two parts - the receiving form, or matrix, and the response form, or punch.

A resin is injected into the mold, which is then polymerized by energy supply. In this case, the resin molecules form bonds with each other, forming a continuous network. The result is a stiff composite product containing fibers and a polymerized resin.

You can also mention the method of molding by infusion of the resin.

This method usually involves several stages, including the placement of fibrous reinforcing elements on the mold.

After that, the mold is closed with a flexible lid, which allows the controlled passage of resin, which is injected inward to the specified reinforcing fibers, and then polymerized to obtain a finished rigid product.

The resin spreads under the action of a driving force resulting from rarefaction at some points of the lid, towards which the resin introduced into the mold moves.

In accordance with traditional infusion technology, the molding tool consists of a molding matrix and a sealed cover such as a casing, serving as a response form.

The molding tool used in the methods discussed above, whether it is the standard RTM method or molding by resin infusion, is quite difficult and is usually designed for the manufacture of products of a special profile. Therefore, if you want to make products of different types, you need to make changes to the equipment, leading to a significant increase in its cost.

In addition, such equipment can have a fairly short life. This is due to the fact that when using the standard equipment for the RTM method, any destruction of the matrix part of the form, or the response form, or both of them inevitably entails the destruction of the entire equipment as a whole.

Finally, due to the complexity of developing a molding tool suitable for manufacturing products from composite types of special types, the technologies under consideration are limited only to the case of manufacturing products having a simple or moderately complex profile and not containing thin parts.

The present invention addresses the above drawbacks.

In this regard, the main objective of the invention is to develop a device for manufacturing products from composite material by the method of injection of resin, which would be less complex and simpler molding equipment compared to that used in the above closed-form systems.

Another objective of the invention is to develop a device for manufacturing products from a composite material by resin injection, the molding tool of which would have the possibility of readjustment, would be easily adaptable to the profile of the manufactured products and at the same time easily replaceable.

It is also desirable to develop a device for manufacturing articles made of composite material by resin injection, which would help to eliminate the disadvantages of RTM methods and methods of molding with resin infusion, while maintaining their inherent advantages.

Thus, another objective of the invention is the development of a device for manufacturing products from a composite material by the method of resin injection, with which would reduce production and time costs for the manufacture and preparation of products from composite material.

As part of the solution of the tasks, a device is proposed for manufacturing a product from a composite material by the method of injection of resin, containing a form where it is supposed to place a workpiece of the product with the ability to impregnate resin. The device is characterized in that the form is divided into a matrix and one or more movable structural elements made with the possibility of adjustable placement on the matrix, and after assembly, the entire resulting assembly forms a cavity, the profile of which corresponds to the profile of the manufactured product.

It should be clarified that the matrix can have any profile.

The proposed device can be characterized by one of the following features, which are considered either individually or in combination:

- the matrix has a flat profile;

- these structural elements, which can be made collapsible, are independent three-dimensional geometric blocks, the profile and dimensions of which correspond to the profile and dimensions of the manufactured product;

- these structural elements, which can be made collapsible, can include flexible or rigid cores of any type, the profile and dimensions of which correspond to hollow structures;

- structural elements provide a uniform distribution of the resin;

- structural elements of the mold are capable of performing the function of a branch pipe;

- the device further comprises injection means configured to provide mixed impregnation of the workpiece with injected resin;

- injection means are distributed over the surface of the mold in such a way that it promotes lateral and / or layer-by-layer diffusion of the resin;

- the device further comprises a sealing system of structural elements in relation to injected into the form of resin.

The subject of the invention is also a method of using the device described above, which includes at least one step, during which one or more movable structural elements of the mold are adjustable to be placed on the matrix in such a way that, after assembly, the entire resulting assembly forms a cavity whose profile corresponds to the profile of the manufactured product.

The method according to the invention may also be characterized by the following feature:

it further includes the step of performing transverse impregnation in relation to the plane of the workpiece and simultaneously layerwise impregnation in relation to this plane of the workpiece.

The essence of the invention, as well as its other features and advantages will become clearer from reading the following detailed description, which is given as an example, not limiting the scope of legal protection of the invention, and is provided with links to the attached drawings, on which:

figure 1 in cross section depicts one embodiment of the proposed device intended for the manufacture of articles of composite material by injection of resin;

figure 2 in a perspective view shows the device shown in figure 1;

figure 3 in a perspective view on an enlarged scale depicts a sealing system shown in figure 2 of the device.

The process of manufacturing a product from a composite material consists essentially of molding the composite element using an appropriate device by injecting liquid resin into a frame of essentially dry reinforcing fibers that are pre-laid in a closed mold and which are pre-shaped to a profile essentially corresponding to the profile of the manufactured product.

Figures 1 and 2 show a device 10 for manufacturing a product from a composite material by resin injection.

This device has a molding cavity (not shown) where a mold 20 is inserted, into which a preform 1 impregnated with resin is placed to obtain a manufactured product from a composite material.

In accordance with the invention, the mold 20 is divided into a molding matrix 21 and one or more independent movable structural elements 22, which are adjustable to be mounted on the matrix in such a way that after assembly of the assembly they all form a cavity, the profile of which corresponds to the profile of the manufactured product.

In this case, the matrix 21 is shown as an example flat.

As for the structural elements 22, they are made with the possibility of movement on the molding matrix 21, depending on the profile of the manufactured products. They are three-dimensional geometric blocks 23 for which such a profile, dimensions, thickness and position on the matrix 21 are chosen so that they correspond to the profile of the manufactured product. This will take into account all the requirements for the manufactured product in terms of geometry, dimensions and thickness.

As it should be understood, the advantage of this form is that it is easy to operate, has the ability to readjust, and it can be adapted to the profile of the products being created.

Indeed, it is possible to create a wide variety of products from a composite material using a single form, resulting in reduced equipment costs.

In addition, when working with such a form, you can easily replace its constituent elements without having to replace the entire form, which allows you to increase the service life of the forms.

With the help of such equipment, it is possible to create, firstly, a blank 1 of reinforcing fibers and, secondly, the final product from composite material.

Figure 1 and 2 presents an example of the invention, not limiting the scope of its legal protection. According to this example, two parallel rows of identical structural elements 22 are placed on the molding matrix 21, allowing you to create a blank 1 with a flat base 2 and protrusions 3.

In accordance with one variant of the invention, such a molding tool can be used for the manufacture of two-dimensional products from a composite material.

In addition, it can be adapted for the manufacture of products of a monolithic structure, multilayer products, or products including hollow cores.

As follows from figures 1 and 2, the device 10 is also equipped with means 30 for closing the created workpiece 1, made in the form of covers placed on the surface of this workpiece 1, not closed by molding structural elements 22. Thus, as shown in figure 1, in accordance with an example that is not restrictive, there are two covers, each of which is laid on the horizontal shelf of the T-shaped protrusions 3 of the created blank 1. These covers allow you to give the upper part of these protrusions an appropriate geometric configuration th.

To enable the preform to be impregnated with 1 resin, the mold 20 is connected to a container with resin (not shown), which is placed inside some heating means (not shown) such as a furnace or any other apparatus of a similar purpose. The specified capacity is associated with form 20 through means 40 of injection of resin.

These means 40 include several resin injectors 41, each of which is connected in a manner known per se from the dispenser 42, the entire assembly being located on a distribution grid 43, which is partially supported by closing means 30.

The injection means 40 is distributed over the entire surface of the mold 20 in such a way as to allow mixed impregnation, i.e. simultaneous or sequential transverse and / or layerwise impregnation of the preform 1 with an injectable resin. The transverse impregnation mode corresponds to the presence of a distribution grid 43, and the layer-by-layer mode corresponds to the absence of this lattice.

The structural elements 22 included in the mold are also configured to uniformly compress the preform 1 and change the proportions of the respective zones covered by the structural elements 22 in the mold 20.

As can be seen in figure 1, the form 20 is connected with the casing 50, which is designed to close it, and also serves as a response form.

This casing is a gas-tight membrane that covers the entire assembly consisting of the molding matrix 21, the workpiece 1 and the molding structural elements 22. It can be made of plastic, resin or any other known material.

In addition, there are provided through channels in which injectors 41, which are part of the resin injection means 40, and outlet pipes, which are described below, can be placed.

The mold 20 is also provided with peripheral sealing gaskets 70, ensuring tightness between the casing 50 and the mold 20, while the entire assembly under consideration forms a sealed space corresponding to the volume of the future product.

In accordance with one embodiment of the inventive device 10, a second casing is provided therein, which ensures tightness and continuous uniform pressing of the preform 1 at the stage of polymerisation of the resin injected into this preform 1.

The injection of the resin is carried out in vacuum. Due to the presence of the casing 50 and the sealing gaskets 70, it is possible to obtain a pressure drop between the outer space and the sealed space, which creates a compressive force during the injection of resin into the workpiece 1 located inside the specified sealed space.

For this purpose, the device 10 is equipped with means 60 for creating a vacuum. These means include a vacuum pump (not shown) connected to the branch pipes 61, i.e. channels for removing gas, which provide the output of air and gases released during the injection of resin into the mold 20.

According to the example shown in FIG. 1, which is not restrictive, a pipe 61 is connected to the upper part of each of the two rows of molding structural elements 22 of the mold 20 and is connected through the flow blocking device 62.

In the preferred case, the function of the branch pipes 61 is performed by molding structural elements 22 of the mold 20, associated with closing means 30.

In addition, in accordance with one embodiment of the invention, the mold 20 can be placed inside any heating device (not shown). As examples of such a device, not having a restrictive nature, mention may be made of a drying chamber, an autoclave or a self-heating form. Thanks to the placement of this device inside the autoclave, it is possible to increase the pressing forces acting on the casing 50 and the driving force causing the transfer of resin into the workpiece 1.

As can be seen in FIGS. 2 and 3, the device 10 may also include a sealing system 80, which prevents the resin injected into the mold 20 into the structural elements 22. This protection is provided by the sealing ring 80.

The following describes the method of using the above device 10.

First, on the molding matrix 21 of the mold 20 of the device 10, a frame of dry fibrous reinforcing elements for manufacturing a product from a composite material is placed.

Then, one or more pre-selected structural elements 22 are applied to the entire workpiece or to any part thereof to obtain a configuration corresponding to the profile of the future product from composite material. As a result, all the protrusions 3 are sandwiched between the matrix 21 and the molding structural elements 22 with the formation of the preform 1.

In the next step, in order to close the mold 20, a casing 50 is put on this entire assembly, under which the injection means 40 and the branch pipes 61 should be previously placed.

If required, a degassing step can also be preliminarily performed, during which gas is removed from the resin in the container to prevent too many bubbles from entering the mold through the channels of the injectors.

If necessary, the resin is heated until the viscosity required to transfer the resin to the workpiece 1 is reached. A thermosetting or thermoplastic resin can be used as the resin.

In the next step, resin is injected using the injectors 41 provided in the device 10.

In a preferred case, the resin is then infused while maintaining the necessary vacuum.

The resin is distributed inside the preform 1, filling the voids separating the fibrous reinforcing elements and impregnating them.

In accordance with the invention, the preform is impregnated with 1 resin either simultaneously or sequentially.

This provides the advantage of providing dimensional tolerances in critical areas of the product (protrusions 3), as opposed to conventional areas where dimensional tolerance may be less rigid.

In addition, due to the ability to place resin dispensers in a set over the entire surface of the mold, the duration of the product manufacturing cycle is reduced, since the injection time itself is reduced.

Due to the vacuum created by the vacuum pump in communication with the branch pipes 61, a pressure differential arises, as already mentioned above, between the sealed space defined by the casing 50 and the mold 20 of the device 10 and the outer space.

As a result of this, the external air creates a compressive force acting on the casing 50, which compresses the molding structural elements 22 and the preform 1, thereby facilitating the infusion of resin into the preform 1.

In the next step, the resin is polymerized either at room temperature or by heating. The resin molecules form bonds with each other, creating a continuous grid. The result is a rigid composite material product consisting of fibers and polymerized resin.

After that, the product from the composite material is removed from the mold, having previously removed the casing 50. The profile of this product is determined by the connection between the molding matrix 21 and the movable structural elements 22 of the mold 20 of the device 10.

It will be apparent to those skilled in the art that, compared with known devices for manufacturing products from composite material, the advantage of the claimed device is that it uses simpler equipment, not limited to only one specific profile of the manufactured product.

It should also be understood that the scope of legal protection of the invention is not limited to the options for its implementation, which are described above only as illustrative examples, but rather covers all kinds of modifications.

Claims (10)

1. A device (10) for manufacturing a product from a composite material by injection of resin containing a mold (20), where it is planned to place a workpiece (1) of an article with the possibility of impregnation with resin, characterized in that the mold (20) is divided into a matrix (21) and one or more movable structural elements (22) made with the possibility of adjustable placement on the matrix (21), and after assembly, the entire resulting assembly forms a cavity, the profile of which corresponds to the profile of the manufactured product. 2. The device according to claim 1, characterized in that the matrix (21) has a flat profile. 3. The device according to claim 1 or claim 2, characterized in that said structural elements (22), which can be made collapsible, are independent three-dimensional geometric blocks, the profile and dimensions of which correspond to the profile and dimensions of the manufactured product. 4. The device according to claim 1 or claim 2, characterized in that said structural elements, which can be made collapsible, can include flexible or rigid cores of any type, the profile and dimensions of which correspond to hollow structures. 5. The device according to claim 1 or claim 2, characterized in that said structural elements (22) are capable of performing the function of a branch pipe (61). 6. The device according to claim 1 or claim 2, characterized in that it further comprises injection means (40) configured to simultaneously or sequentially impregnate the preform (1) with an injected resin. 7. The device according to claim 6, characterized in that the said injection means (40) are distributed over the surface of the mold (20) in such a way that it promotes transverse and / or layer-by-layer diffusion of the resin. 8. A device according to any one of claims 1, 2, 7, characterized in that it further comprises a system (80) for sealing structural elements (22) with respect to the resin injected into the mold (20). 9. The method of using the device (10) according to any one of the preceding paragraphs, characterized in that it includes at least one step, during which one or more movable structural elements (22) of the form with the possibility of regulation are placed on the matrix (21) so that after assembly, the entire assembly obtained forms a cavity, the profile of which corresponds to the profile of the manufactured product. 10. The method according to the preceding paragraph, characterized in that it further includes the step of performing transverse impregnation in relation to the plane of the workpiece (1) and / or layer-by-layer impregnation in relation to this plane of the workpiece (1).

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